Dental and medical hypodermic syringe



Feb. 14, 1939. E. .1. CHAPUT DENTAL AND MEDICAL HYPODEEMlC SYRINGE Filed July 9, 1937 2 Sheets-Sheet 1 Feb. 14, 1939. E. J. CHAPUT Q DENTAL AND MEDiCAL HYPODERMlC SYRINGE Filed July 9, 1957 2 Sheets-Sheet 2 Patented Feb. 14, 1939 PATENT OFFICE DENTAL AND MEDICAL HYPODERMIC SYRINGE Elmer J. Chaput, Detroit, Mich.

Application July 9, 1937, Serial No. 152,850

2 Claims.

The object of my invention is to provide a novel and eflicient dental and medical hypodermic syringe having a novel mode of operation and a novel combination of elements described and claimed.

I attain these and other objects of my invention by the mechanism illustrated in the accompanying drawings, in which- Figure l is a front elevation of the invention;

Fig. 2 is a section of line 2-2 of Fig. 1;

Fig. 3 is a section of line 3-3 of Fig. 1;

Fig. 4 is a side elevation of the invention with the handle elements removed;

Fig. 5 is a front elevation of the outer cylindrical member;

Fig. 6 is aside elevation of same;

Fig. 7 is a view partly in side elevation and partly in section of the hypodermic needle,'somewhat enlarged;

Fig. 8 is a top plan view of the hypodermic needle;

Fig. 9 is a detail perspective view of member I4;

Fig. 10 is a view partly in elevation and partly in longitudinal section of members 26 and 28;

Fig. 11 is a view partly in elevation and partly in longitudinal section of members 26, 28, 3| and 33; and

Fig. 12 is a detail view of the cork.

Like numerals designate like parts in each of the several views.

Referring to the accompanying drawings I provide a syringe outer casing I, having a cut-out portion 3 extending nearly the entire length of the casing, as showmin Figs. 1, and 4, the lower end of the cut-out portion being designated as 4 and the upper end of the cut-out portion being designated as 6. Near the upper end of the cutout portion opposite additional cut-out portions are recesses 5. The inner wall of the casing i is designated as 2 and the hollow upper end or the casing is designated as 1. The casing has a lower rounded end 9 and an interior frustoconical chamber Ill. The channel ll extends longitudinally through the casing I from the apex of the frusto-conical chamber l0. As shown in Figs. 5 and 6, I provide a transverse slot l2 in the casing to receive the hypodermic needle latch I 4 which is hingedly mounted on the spaced ears l3 by the hinge pin l9. Latch l4 which is inserted through the aperture I6 in shank ii of the latch M has a projecting free end I8, as shown in Fig. 1.

I provide a hypodermic needle 2| having a longitudinal channel 22 extending from end to end through same. Needle 21 has a frustoconical shank 20 seatable in a corresponding shank chamber ll) of the syringe casing. The needle is provided with a cylindrical shank 25, an annular flange 23 adjacent shank 25 and an annular groove 24 adjacent said annular flange. As shown in Figs. 1 and 2, a glass tube 26 is mounted in the syringe casing 1. Near the end of the glass tube is an inner annular flange 21 which engages a corresponding annular recess 21a 10 in the extension 28 of the rubber washer 29. The rubber washer 29 has a novel feature of a longitudinal channel 39 for the passage of fluid to be injected. This channel is capped in any of various ways as by the lead cork 3|, as shown in 15 Fig. 11, or by caps made of wax, Cellophane, rubber, or metal which caps the entire end or the tube. The provision of this channel 30 through the rubber washer is an entirely novel feature, as heretofore it has been necessary for the needle to pierce the rubber washer. At the other end of the glass tube 28 I provide a suitable rubber plunger or piston 32. As shown in Figs. 1 and 2, I provide a piston rod 34 of smaller diameter than the inside wall 2 of the casing i whereby to provide an annular chamber 33 encircling the piston rod 34, as shown in Fig. 2. Piston rod 34 has a threaded end 35 engaging a threaded socket 36 of the handle 31. I provide a fixed handle 38 screw-threaded at 39a to the detachable shank 39 of the syringe casing I; said shank 39 being screw-threaded at 8 to the hollow integral shank 1 of the syringe casing i. Detachable shank 39 has a central channel 40 in which piston rod 34 is slidably mounted. As 35 shown in Figs. 4 and 5, I provide an aperture 42 through casing l for the admission of air to prevent a. vacuum in the chamber 33, which would interfere with the proper operation of the instrument. The channel 30 is of suitable size to receive the cylindrical shank 25 of the hypodermic needle 2|. The flange 21 on the glass tube 26 and the corresponding groove 21a. in the rubber washer 29 retain the rubber washer 29 in place. It thus prevents the rubber washer from being forced up into the tube or from any possibility of pulling it out of the tube. As this rubber washer has a longitudinal channel 30, which receives the shank of the hypodermic needle, its allows the solution to escape when the piston rod actuating piston 32 forced downward through the glass tube 26, whereby injection takes place. This is the only way the solution can come out of the tube during the injection. Member 32 always stays in the glass tube to close the tube.

To hold the solution in the tube and prevent any of the fluid from escaping, a suitable cap such as a lead cork Si is used to close the channel 30 and seal the tube. When making an injection the following takes place: The leadcork 3| (or other cap over the channel 30) is removed from the tube, the glass tube is placed in the syringe chamber 2 forcing the rubber washer into place, thereby causing a tight fit at this point of the needle end. This completes the syringe and it is now ready to make an injection.

Among the advantages of this syringe is that it is simple in construction and easy to clean and it has an improved needle latch I4 which is easy and simple to use. To remove the needle all that is necessary is to open the latch it, invert the syringe and the needle drops out. To put the needle in place, the latch l4 being open, place the needle in the syringe. chamber, tilt the syringe endwise with the end 9 downward and the needle will seat itself in the socket I0, then close the latch l4 and the syringe is ready for operation.

In the prior art it has been customary for the needle to pierce the rubber washer. This procedure is eliminated in my hypodermic syringe by providing a novel rubber washer with a longitudinal channel through same. This channel may be corked or capped in any suitable manner as by caps made of wax, Cellophane, rubber, or metal.

- of a casing having a cut-out portion extending for most of the length of the casing, a hypodermic needle having an enlarged shank seating in one end of the casing, the needle projecting through the casing, a glass tube removably mounted in the casing, said tube having interior annular flanges, a rubber washer mounted in the end oi the glass tube and having recesses corresponding in size and position with the flanges of the glass tube to be engaged thereby, said washer having a longitudinal channel extending therethrough, adapted to receive removable means for capping the outer end of the aforesaid washer, the shank of the needle having an annular groove therein. and a latch hihgedly mounted on the casing and swingable into position to engage the groove of the shank of the needle for releasably holding the needle in the casing.

ELM AER J. GHAPUT. 

